<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>P44 2.5.4案例打印金字塔</title>
</head>

<body>
    <script>
        var level = prompt('请设置金字塔的层数');
        level = parseFloat(level) && Number(level);
        if (isNaN(level)) {
            alert('金字塔层数必须是纯数字');
        }
        for (var i = 1; i <= level; ++i) {
            var blank = level - 1;
            for (var k = 0; k < blank; ++k) {
                document.write('&nbsp;');
            }
            var star = i * 2 - 1;
            for (var j = 0; j < star; ++j) {
                document.write('*');
            }
            document.write('<br>');
        }
    </script>
    <a href="../首页/page02.html">
        <h2>返回上一页面</h2>
    </a>
</body>

</html>